Hi all.
My neighbour dropped his 9.9 (10r79b) to me with idle issues and a pain to start sometimes.
I dropped it in a barrel of water and it started first pull with the choke on, pushed choke in and it continued to run. Working like a charm. In neutral you can give it a bit of throttle and i revved it up and down and all seemed good. I noted that the engine had a bolt to stop you retarding the timing and at lowest revs the throttle blade was just shut. When giving it a rev up it it was slow to respond, i thought maybe it had dropped a cylinder but putting it in gear and revving it it had plenty of balls.
I put a spark plug tester and had spark across both cylinders with about a cm of airgap. (have not checked colour at night)
Compression 90psi on bot pots. (can start easily first pull so this seems good)
Popped flywheel and keyway is fine.
Disconnected kill switch.
Rebuit carb, popped out welsh plug and made sure 3 holes for idle circuit are clean. Could not get small white plastic seat for the needle out, tried easy out and screws, not sure it ever had one so put one in anyway.
Again motor started first pull and kept running. After a minute or two it started to be slow to respond to the throttle. A slight squirt of fuel down the carb throat seemed to help most times. Then suddenly it would cut out and refuse to start. Rechecked spark repeatedly and ran engine till it cut out again. Even after pulling plugs and turning over then reinserting plugs it would not fire sometimes.
Threw compression gauge on it again and got 70psi on each pot. I thought this would have gone up when warm????? This could be the cause i would assume.
Thoughts people??? This has me scratching my head.
Cylinder head?
lower crank seal?
Reid Valves?
Fuel filter gasket.
I have squirted fuel around the motor to se if its sucking in anything anywhere but no change.
I am leaning towards head gasket but don't want to do it unless i have to.
My neighbour dropped his 9.9 (10r79b) to me with idle issues and a pain to start sometimes.
I dropped it in a barrel of water and it started first pull with the choke on, pushed choke in and it continued to run. Working like a charm. In neutral you can give it a bit of throttle and i revved it up and down and all seemed good. I noted that the engine had a bolt to stop you retarding the timing and at lowest revs the throttle blade was just shut. When giving it a rev up it it was slow to respond, i thought maybe it had dropped a cylinder but putting it in gear and revving it it had plenty of balls.
I put a spark plug tester and had spark across both cylinders with about a cm of airgap. (have not checked colour at night)
Compression 90psi on bot pots. (can start easily first pull so this seems good)
Popped flywheel and keyway is fine.
Disconnected kill switch.
Rebuit carb, popped out welsh plug and made sure 3 holes for idle circuit are clean. Could not get small white plastic seat for the needle out, tried easy out and screws, not sure it ever had one so put one in anyway.
Again motor started first pull and kept running. After a minute or two it started to be slow to respond to the throttle. A slight squirt of fuel down the carb throat seemed to help most times. Then suddenly it would cut out and refuse to start. Rechecked spark repeatedly and ran engine till it cut out again. Even after pulling plugs and turning over then reinserting plugs it would not fire sometimes.
Threw compression gauge on it again and got 70psi on each pot. I thought this would have gone up when warm????? This could be the cause i would assume.
Thoughts people??? This has me scratching my head.
Cylinder head?
lower crank seal?
Reid Valves?
Fuel filter gasket.
I have squirted fuel around the motor to se if its sucking in anything anywhere but no change.
I am leaning towards head gasket but don't want to do it unless i have to.